2 different pump losing prime overnight

[Eilum]

My neighbor asked me to help him because his pump was.losing prime overnight.

Replaced lid o-ring, replaced multiport, looked for suction side leaks. Found nothing. But still losing prime an hour or two after shutting off pump.

Then, randomly, my pool started doing the same thing. Replaced pump cover lid with o-ring. Can't find any air leak.

We are baffled.

 

[reggiehammond]

Lube and check both drain plugs on pump (most have two)?

Obviously there's a very small air leak somewhere - not large enough to cause operational issues, but enough to cause issues once stopped. Do you have a check valve before pump on skimmer lines? That might help keep enough water in the pump to cut down on priming time if the air leak is behind it.

 

[Eilum]

Thank you. Wouldn't I see water leaking from the drain plugs if they were loose?

Also, could the air leak be from the pressure side? I have an offline chlorinator that makes a sucking noise every time the filter is turned off. Is it possible that the air is coming back through the pressure side lines to the filter and down through the pump basket?

 

[Eilum]

SOLVED
For anyone who is losing prime overnight. I replaced the pump lid o ring. I tightened the drain plugs with a wrench (I know that is not recommended). I took out my offline chlorinator. Still nothing.


Pool guy said I need to have someone take apart the pump and replace the pump seal.

But it was the filter drain cap. It was hand tightened but I tightened it with a wrench and the air leak stopped.


If you lose prime and you see no air or water leak, tighten your plugs and caps.